Lightweight enclosures that provide some protection from environmental conditions are known, such as tents, bivy bags, bivy sacks, and the like. Polyester and nylon materials used to construct lightweight enclosures are coated to provide water resistance or waterproofness, and can be printed to achieve a desired aesthetic.
Lightweight tent constructions are typically considered as having either a double wall construction that has a separate rain fly and tent body, or a single wall construction having only a tent body comprised of, for example, a laminate material, and having no separate rain fly. Double wall tents rely on a rain fly to provide waterproofness by being positioned over a tent body otherwise constructed of highly air permeable and water permeable mesh wall fabric. However, the addition of the rain fly adds weight and bulk to the overall total construct. Also, double wall tent products having a lightweight rain fly material, such as nylon, typically use a polyurethane coating or silicone coating for waterproofness. Disadvantageously, coated materials fail to provide long-term waterproof durability. Typical laminates used for single wall tents have many layers to insure long-term water resistance, but as a result, are heavy and have high water weight gain when rained upon thereby making them unsuitable for certain applications. Moreover, the laminates of single wall tents are not air permeable and typically lack sufficient oxygen permeability to sustain the life of the occupants when the tent is closed, and often lack adequate flame resistance.
Coatings are frequently applied to enclosure materials to achieve flame resistance and UV stability; however, the coatings are susceptible to cracking in cold climates, as well as abrasion and other mechanical challenges that may induce failure. Alternatively to achieve flame resistance, flame-resistant materials, such as those sold under the tradename Nomex®, are often used. Unfortunately, these meta-aramid textiles show significant deterioration of tensile strength after exposure to UV radiation, a common challenge in the field.
Tents formed as a single wall construct can have lower weight and less bulk than the double wall tents by eliminating the waterproof fly. However, current lightweight single wall constructions using coated lightweight materials such as coated nylon, do not have long-term liquid resistance and do not reliably pass certain flame resistance requirements that are important to some tent users. Single wall tents using materials that can achieve higher levels of flame resistance use multiple layers of higher weight fabric, adding bulk and weight to the construct.
Composite waterproof fabric for enclosures have been described. For example, in U.S. Pat. No. 4,302,496, composites for tent walls are described that are reported to be lightweight and flame or fire resistant. The composite has at least three plies, namely a outer woven ply and an inner woven ply, and a middle ply of polytetrafluoroethylene. It is stated that tensile strength and tear resistance are imparted to the composite by the inner woven ply, while abrasion resistance is provided to the composite by the outer woven ply, and waterproofness and wind resistance are provided by the middle ply. Despite the description of the composite as lightweight, the composite fabric embodiments described disadvantageously have a weight reported to exceed 5.4 oz/yd2 making it too heavy and bulky for certain applications.